Smell loss is a significant health and safety problem for millions of Americans. Unfortunately, clinical assessment of smell function is not routinely performed because a rapid inexpensive and valid test of olfaction is not available. An improved test would enhance the detection and treatment of smell loss and several neurodegenerative diseases, including Alzheimer's disease. The goal of the proposed project is to develop a new test based on exploratory sniffing behavior. Preliminary studies show that people with a normal sense of smell reduce sniff magnitude when they encounter a malodor, while people who have lost their sense of small do not. The feasibility of this approach will be demonstrated by showing that the sniff test possesses psychometric and practical features that make it superior to alternative tests. Phase II funding will be used to conduct additional validity tests and to develop a commercial version of the sniff test. Development of the sniff test device will provide clinicians with a method of evaluating olfactory function that is valid irrespective of a person's age, cultural background or state of intellectual function. This test will permit standardized, widespread and routine testing of the sense of smell, and thus improve the diagnosis and treatment of smell loss. PROPOSED COMMERCIAL APPLICATIONS: Over 42 million Americans are at-risk for olfactory loss. Based on the cost of the most widely-used clinical test of olfaction (the UPSIT) an estimate of the commercial potential of an improved olfactory test is of the order of $1 billion. Since the sniff test crosses barriers of language and cultural, there is a clear opportunity to access a much larger international market, estimated at 260 million people.